Printing machine



April 26, 1932. A LANGSNER PRINTING MACHINE Filed Aug. 51, 1931 2 Sheets-Sheet Patented Apr. 26, 1932 UNITED STATES ADOLPI-I LANGSNER, OF CHICAGO, ILLINOIS, ASSIGNOR CHICAGO, ILLINOIS, A CORPORATION r EUGENE mnrzenn 00., or or DELAWARE PRINTING MACHINE Application filed August 31, 1931. Serial No. 560,400.

This invention relates to photoprinting apparatuses and more specifically to improvements in printing machines of the general class represented in mv copending applica- 'tion, Serial No. 420,170, filed January 11,

The main objects of this invention are to provide-such a printing machine of increased capacity for a given size; to provide in such 10, a machine an improved and simplified form of work holding wrapper or curtain roller and mounting means therefor; to provide also an improved and simplified and more efficient roller tensioning and holding means;

" 15 and to provide such an improved tensioning means as wherein and whereby the roller cable slack can be most assuredly and readily taken up. 1

Several illustrative embodiments of this 7 ioinvention are shown by the accompanying drawings in which:

Figure 1 is a front elevation of a single curtain printing apparatus having a work receiving platen of semi-circular cross section, and shows my improved curtain mounting with a vertically arranged single tensioning spring.

Fig. 2is a somewhat fragmentary side elevation of a double curtain printing apparatus or duplex machine having a cylindrical work receiving platen, and shows one manner of mounting and tensioning the cords for the two curtains by means of a single vertically arranged spring.

Fig. 3 is a perspective detail view, somewhat enlarged, showing the method of "mounting the tension cable pulleys of the device shown in Fig. 2.

Fig. 4 is an enlarged section on line 44 of Fig. 1.

Fig. 5 is a detail of another method of adjustably securing the ends of the tensioning cables, the dotted portion representing the position of a second curtain and cable as used in the double platen or cylindrical 7 machine.

Fig. 6 is a detail showing a third method of securing the tensioning cables, wherein the 50 dotted portion represents the arrangement of a second curtain and cable of a double machine.

Fig. 7 is a sectional detail of the cable pulleys taken on line 77 of Fig. 6",;

Fig. 8 is a horizontal section on the line 8-8 of Fig. 2.

As shown in the drawings, especially Figs. 1 and 2, the photoprinting apparatus is supported on an angle iron frame 1 having a pair of vertical wooden posts 2 against which the ends of an arcuate transparent work receiving platen 3 are secured. The said platen 3 is further secured and supported by means of the upper and lower angle iron retaining rings 4 which constitute a part of the frame.

Mounted on one of the posts 2 which projects somewhat above the top of the work platen 3 is a davit-like arm 5, carrying a pulley 6 over which is suspended a vertically movable lamp 7 by means of a cable 8. Said cable passes downward under a pulley 9 and then over another pulley 10 from which it passes to a counterpoise which is not shown. The pulley 10 is geared to a multiple dashpot damping mechanism 11 which serves to control the rate of travel of the lamp 7.

Mounted on the retaining rings 4 and arranged to travel over the platen 3 is a curtain roller 12 on which is wrapped a work holding curtain 13. One end of curtain 13 is secured to one of the posts 2 by means of a binding strip 14. I

Cable drums 15 are mounted, one on each end of the roller 12; and cables 16 and 17 are wound, one on each drum, differentially relative to the curtain 13. The drum end of each cable is fastened to the respective drum on which it Winds.

On the single curtain machine, as shown in Figs. 1 and 4, the cables 16 and 17 pass from the drums 15 over cable pulleys 18 and 19 respectively; and the ends are joined by means of the tension spring 20. In order to provide adjustability of tension in the cables the ends are passed through the end eyes of the spring 20, doubled back and secured to the cable body, each by means of a clamp 21.

On the double curtain machine, as shown in Figs. 2 and 8, the top and bottom cables 16 and 17 respectively of each curtain roller 12 are secured to a common tension spring 20, in the same manner as shown in the single curtain device of Fig. 1; and each cable passes over its own pulley, the pulleys being mounted 111 pairs in the manner shown 1n Fig. Each pair of pulleys is journaled on a common spindle 22 mounted on the appropriate post 2; and each cable is provided with its own adjustment clamp 21. The curtains of the double machine are secured to the post located on the opposite side of the machine from the cable tensioning spring, (see Fi 8) in substantially the same manner as the curtain of the single device shown in Fig. 1. In this embodiment the two platen segments 13 are set between thev two posts 2; and one curtain 13 operates over each platen: 3.

In Fig. 5 is shown another method of mounting and securing the cable tensioning spring 20. In this case the cable, instead of being: passed over a pulley, is secured to a tensioning. spring mounted on the retaining ring t. The tensionin'g spring 20 in this case is fastened to an eye-bolt 2? which passes through a bracket 24 and is adjustably secured thereto by the nuts 25. The adjustment. of the cable slack is provided for'by the clamp 21 in thesame manner as the cables of the single device shown in Fig. 1'.

A third arrangement for mounting the cable temsi-oning means is shown in Fig. 6 in which case each cable is passed over a pulley and. then securedto a tensioning spring which in turn is secured to a bracket mounted on the ring 4. In this case each pair of cable pulleys is journaled on a shaft or spindle mounted on the ring 4.

In each of the optional arrangements shown in Figs. 5 and 6 a cable tensioning spring 20 is provided for each cable; and the springs are mounted on the corresponding angle iron retaining rings, two at the top and two at the bottom respectively.

In operation, tension is provided in cables 16 and 17 by loosening the clamp 21 and then pulling the cables taut after which the clamps 21 are tightened to secure the cable ends.

After the cables have been adjusted for tension, the curtain rollers 12 will be held snugly against the angle iron retaining rings 4; and there will be an equal tension in any curtain '13 and in its cables 16- and 17 combined.- This equality of tension in the curtain and cables is determined by the difi'erential winding of the cables, on their respective drum, relative to the direction on which the curtain 13 is wound on the roller 12.

The curtain rollers are freely operated manually by merely rolling them in the direction desired; and because of the equal tenin both the curtain and the cables, the roller will. rest in whatever position it may happen to be left. After a period of. use the cables 16 and 17 will usually stretch to a certain extent and lose some of their tension. However, the cables can be easily and rapidly retensioncd by merely loosening the clamps 21 and pulling the cables taut.

In order to assure equipoise in operation, and in. order that the cables may always have the same tension regardless of the position of the curtain roller on the machine, the cable drums'15 are conoidal'ly formed and provided 7 with spiral grooves, so that the diameter of the curtain roller plus the thickness of the curtain turns thereon will always be the same as the diameter ot the cable drum 15 through the leading groove on which the cable is being 30 wound or unwound. This form of cable drums being old and well known in the art needs no further explanation.

The advantages accruing from the application of the herein described invention to photoprinting apparatus lies mainly in the rapid and easy manner in which the cable tension may be adjusted and in the low manufacturing cost of the cable and tensioning arrangement. Heretofore it has been necea-J sary to use either the clumsy and inefiicient floating counter-weight method of cable tensioning or the complicated and costly arrangement whereby coiled tensioning springs are provided at each end of the curtain rolleru; P The improvements herein set forth have great advantage over such curtain roller'spring devices, being far easier to adjust in order to provide the proper cable tension.

Although several specific embodiments of Q this invention are herein shown and described, it is to be understood that details of the construction shown may be altered or omitted without departingfrom the spirit oi the invention as defined by the following claimsiti I claim:

1. In a photoprinting apparatus comprising a frame supporting a work receiving platen and a lamp in printing relation thereto, a curtain, a curtain roll arranged to lay and secure said. curtain against. said platen, one end of said curtain being fastened to said frame,,a cable winding drum at each end of said. curtain roll, a pair of cables each arranged to wind difierentially relative to said {L curtain on said drums respectively and having an end secured thereto, and a s ri tensionally connecting the other on 0 said cables.

2. In a photoprinting apparatus compris- CA ing a frame supporting a work receiving platen and a lamp in printing relation thereto, a curtain, a curtain roll arranged to lay and secure said curtain against said platen, one end of said curtain being fastened to said 53 frame, a cable winding drum at each end of said curtain roll, a pair of cables each arranged to wind differentially relative to said curtain on said drums respectively and having an end secured thereto, spring means sac-1B cured to the other ends of said cables and arranged to provide tension in said cables, and tensional adjustment means to secure said cables to said spring means.

3. A duplex photoprinting machine comprising a frame, a pair of substantially semicylindrical transparent platens disposed in cylindro-complementary relation, curtain means for applying print Work thereto respectively, tensioning means common to said curtains, and a common interior source of printing light and light control means there- 4. In a printing device of the class described, equipoise curtain tensioning means comprising a helical spring and a pair of cords connected to the ends thereof respectively and extending to and operatively connected to the end drums of a curtain roller.

5. In a device of the class described, a pair of Work holding curtains, rollers for said curtains, and common equipoise tensioning means therefor.

Signed at Chicago in the county of Cook and State of Illinois this 28th day of August,

ADOLPH LANGSNER. 

